Abstract
Specific antibody concentration in human sera was determined by the end point method using double antibody solid phase radioimmunoassay (SP-RIA). The concentration of standard IgG at the end point was measured with sandwitch SP-RIA, and used as standards for determining antibody concentratlons in human sera. Error extents of the sensitivity of double antibody SP-RIA showed within 10-fold ranges, and its minimum detection levels gave the values from 1.42 to 4.25ng/ml. When the SP-RIA was applied to determine human antibody, 11 of 102 samples were judged as anti-FBS antibody positive samples. The positive distribution ranges revealed the values from 50.5 to 455.5ng/ml of anti-FBSantibody concentrations.